Coastal Georgia Sound Science Initiative

Introduction

The Coastal Georgia Sound Science Initiative is a program of scientific and feasibility studies to support development of Georgia Environmental Protection Division's final strategy to protect the Upper Floridan aquifer from saltwater contamination.

THIS PROJECT HAS BEEN COMPLETED AND IS BEING ARCHIVED IN ITS FINAL CONFIGURATION

USGS Announces First Real-Time Monitoring Wells in Coastal Georgia

To provide information needed to help protect fresh ground-water resources in the Brunswick-Glynn County area, the U.S. Geological Survey (USGS) installed continuous ground-water-level monitors in five wells completed in the Upper Floridan aquifer. These wells are equipped with satellite telemetry to enable real time viewing of data on the World Wide WEB. These are the first wells to be equipped with real-time instrumentation in the 24-county coastal area of Georgia and will provide water managers with immediate data on changing ground-water-level and water-quality conditions. Funding for the wells was provided by the USGS and the Georgia Environmental Protection Division as part of the Coastal Sound Science Initiative, and by the City of Brunswick and Glynn County as part of the Cooperative Water Program with USGS. Additional instrumentation to be installed at the sites will monitor the specific conductance of ground water in the Upper Floridan aquifer, and provide a warning of saltwater contamination into freshwater zones. Data for these and other well sites can be accessed on the USGS Web page.

Project description

Rapid population growth in coastal Georgia, increased tourism, and sustained industrial activity have adversely affected coastal Georgia's water resources and limited the available water supply. The main source of water supply in the coastal area is the Upper Floridan aquifer, an extremely productive water source, which was first developed in the late 1800's, and has been used extensively in the area ever since. Pumpage from the aquifer has resulted in several problems including:

substantial water-level declines

migration of seawater into the aquifer at the northern end of Hilton Head Island, South Carolina;

contamination of the aquifer from underlying brine-filled strata at Brunswick, Georgia;

decreased ground-water inflow to springs, freshwater ponds, marshes, and wetlands, which could impact the balance of freshwater and saltwater in tidal rivers and estuaries;

Saltwater contamination has constrained further development of the Upper Floridan aquifer in coastal Georgia and created fierce competing demands for the limited fresh water supply. The Georgia Environmental Protection Division (GaEPD) released an interim strategy in April 1997 to manage saltwater intrusion in the Upper Floridan aquifer. As part of this interim plan, GaEPD has capped permitted withdrawal from the Upper Floridan aquifer at 1997 rates in the Savannah and Brunswick areas, and has funded a program of scientific and feasibility studies (Coastal Sound Science Initiative) to support development a final water-management strategy. Implementation of the final water-management strategy is scheduled for January 2006.

USGS has studied saltwater contamination of the Upper Floridan aquifer in coastal Georgia for over 50 years through the cooperative water resources program. In support of the Sound Science Initiative, the USGS is working on a comprehensive program to evaluate ground-water flow, saltwater contamination, and alternative water sources of ground water in the coastal area of Georgia and adjacent parts of South Carolina and Florida. The study is being conducted in cooperation with GaEPD and the Georgia Water Resources Research Institute. Project activities include:

offshore drilling near Savannah and Hilton Head Island;

drilling of deep test wells onshore;

evaluation of alternative water supplies in man-made seepage ponds;

ground-water monitoring; and

simulation of saltwater intrusion using digital ground-water models

Introduction

Saltwater contamination is restricting the development of ground-water supply in coastal Georgia and adjacent parts of South Carolina and Florida. The principal source of water in the coastal area is the Upper Floridan aquifer, an extremely permeable and high-yielding aquifer, which was first developed in the late 1800’s. Pumping from the aquifer has resulted in substantial ground-water-level decline and subsequent saltwater intrusion of the aquifer from underlying strata containing highly saline water at Brunswick, Georgia, and with encroachment of seawater into the aquifer at the northern end of Hilton Head Island, South Carolina. The saltwater contamination at these locations has constrained further development of the Upper Floridan aquifer in the coastal area and has created competing demands for the limited supply of freshwater.

The Georgia Department of Natural Resources, Georgia Environmental Protection Division (GaEPD) has restricted permitted withdrawal of water from the Upper Floridan aquifer in parts of the coastal area (including the Savannah and Brunswick areas) to 1997 rates, and restricted total new pumpage in all 24 counties to an additional 36 million gallons per day above 1997 rates. These actions have prompted interest in alternative water-management scenarios and in the development of supplemental sources of water supplies including the shallower surficial and upper and lower Brunswick aquifers, and the deeper Lower Floridan aquifer

Coastal physical setting

The coastal area of Georgia and adjacent parts of South Carolina and Florida is part of the Coastal Plain physiographic province of the Atlantic Coastal Plain. The area consists of barrier islands, marshes, plains, a series of terraces, and inland rolling hills and valleys. Land use is urban and industrial in cities such as Savannah and Brunswick; outside these areas, land use is a combination of forest, grazed woodland, cropland with pasture, and marsh and swampland. In 1997, ground-water sources served a population of about 526,600; surface-water sources served about 8,000 (Fanning, 1999). Average annual precipitation ranges from about 46 to 54 inches.

Abu-Ruman, Malek, and Clarke, J.S., 2001, Preliminary simulation of pond-aquifer flow and water availability at a seepage pond near Brunswick, Georgia: in Proceedings of the 2001 Georgia Water Resources Conference, held March 26-27, 2001, at the University of Georgia, Kathryn J. Hatcher, editor, Institute of Ecology, The University of Georgia, Athens, Georgia.

John S. Clarke, D.F. Payne, and W.F. Falls, 2005, Coastal Sound Science Initiative 2005--what have we learned?, Proceedings of the 2005 Georgia Water Resources Conference, held April 25–27, 2005, at the University of Georgia. Kathryn J. Hatcher, editor, Institute of Ecology, The University of Georgia, Athens, Georgia.

Clarke, J.S., and Krause, R.E., 2000, Use of ground-water flow models for simulation of water-management scenarios in the coastal area of Georgia and adjacent parts of South Carolina: in Proceedings of the 2001 Georgia Water Resources Conference, held March 26-27, 2001, at the University of Georgia, Kathryn J. Hatcher, editor, Institute of Ecology, The University of Georgia, Athens, Georgia., p. 627-630.

Falls, W.F., Harrelson, L.G., Conlon, K.J., and Petkewich, M.D., 2001, Hydrogeology and water quality of the Lower Floridan aquifer, coastal Georgia: in Proceedings of the 2001 Georgia Water Resources Conference, held March 26-27, 2001, at the University of Georgia, Kathryn J. Hatcher, editor, Institute of Ecology, The University of Georgia, Athens, Georgia, p. 652-655.

Krause, R.E., and Clarke, J.S., 2001, Saltwater contamination of ground water at Brunswick, Georgia and Hilton Head Island, South Carolina: in Proceedings of the 2001 Georgia Water Resources Conference, held March 26-27, 2001, at the University of Georgia, Kathryn J. Hatcher, editor, Institute of Ecology, The University of Georgia, Athens, Georgia, p. 756-759.

Laitta, M.T., 2001, Linkage of Offshore and Onshore Hydrogeologic Data for Coastal Georgia and adjacent parts of South Carolina and Florida using a Geographic Information System: in Proceedings of the 2001 Georgia Water Resources Conference, held March 26-27, 2001, at the University of Georgia, Kathryn J. Hatcher, editor, Institute of Ecology, The University of Georgia, Athens, Georgia, p.764-767.

Peck, M.F., 1999, Water levels in the Upper Floridan aquifer in the coastal area of Georgia, 1990-98: in Proceedings of the 1999 Georgia Water Resources Conference, held March 30-31, 1999, at The University of Georgia, Athens, Georgia, Kathryn J. Hatcher, editor, Institute of Ecology, The University of Georgia, Athens, Georgia.

Peck, M.F., Clarke, J.S., Abu-Ruman, Malek, and Laitta, M.T., 2001, Hydrogeologic Conditions at Two Seepage Ponds in the Coastal Area of Georgia, August 1999 -- February 2001: in Proceedings of the 2001 Georgia Water Resources Conference, held March 26-27, 2001, at the University of Georgia, Kathryn J. Hatcher, editor, Institute of Ecology, The University of Georgia, Athens, Georgia.

Warner, Debbie, and Aulenbach, B.T., 1999, Regression technique for removing effects of tides and pumpage from ground-water levels during an aquifer recovery test at St Marys, Georgia: in Proceedings of the 1999 Georgia Water Resources Conference, held March 30- 31, 1999, at The University of Georgia, Athens, Georgia, Kathryn J. Hatcher, editor, Institute of Ecology, The University of Georgia, Athens, Georgia.